href="#fb3_img_img_814c49dc-8f04-5843-bef1-ae3228bec837.jpg" alt="Photos depict the corkscrew of endotracheal tube for digital intubation"/>
Figure 3.5 Corkscrew of endotracheal tube for digital intubation
A lighted stylet is a semirigid stylet equipped with a battery‐powered lighted tip [39]. The rescuer inserts the stylet through the endotracheal tube and bends the combination into a “hockey stick” shape. The rescuer then inserts the stylet/endotracheal tube combination blindly into the oropharynx and uses the light to facilitate movement of the tube through the vocal cords. When properly placed, the illumination bulb of the lighted stylet is visible through the patient’s cricoid membrane. Few EMS agencies use lighted stylet intubation due to the cost of the device and difficulty of the technique. Furthermore, the procedure is limited by the need for low ambient lighting.
In retrograde intubation, the rescuer places a large‐bore needle through the cricothyroid membrane, pointing it cephalad, and then inserts a guidewire through the needle, advancing it superiorly until the wire tip comes out through the mouth. A conventional endotracheal tube can then be threaded over the guidewire and through the vocal cords. It is important that the wire be threaded through the “Murphy’s eye” of the tube. Commercial kits exist for retrograde intubation. Only limited data support this technique in the prehospital environment [40].
The Gum elastic bougie, an adjunct for orotracheal intubation, is essentially a semirigid stylet (Figure 3.6). The rescuer performs conventional orotracheal laryngoscopy, placing the bougie through the vocal cords and into the trachea. Because the bougie is smaller and stiffer than an endotracheal tube, it is usually easier to place through the vocal cords. The angled, “hockey stick” tip also provides tactile feedback from the tracheal rings, assuring that the device is in the correct endotracheal position. The rescuer can then slide a conventional endotracheal tube over the bougie and through the vocal cords before removing the bougie. The bougie can also be used as a “tube changer” in the event of balloon rupture, clogging of the tube with vomitus, or other problems. A randomized trial found higher first‐pass ETI success with bougie use during emergency department rapid sequence intubations [41]. Limited data describe improved ETI success with bougie use in prehospital intubations [42, 43].
Figure 3.6 Gum elastic bougie threaded into an endotracheal tube. The bougie is often placed in the trachea with direct laryngoscopy first and the endotracheal tube then threaded over it.
Supraglottic airways
SGAs are advanced airway devices used to facilitate ventilation without conventional endotracheal tubes [44]. Other terms commonly used to describe SGAs include “extraglottic airway,” “rescue airway,” “secondary airway,” “failed airway device,” “difficult airway device,” “salvage airway,” “alternate airway,” and “backup airway.” In current prehospital practice, EMS personnel typically reserve SGAs use for situations with failed ETI efforts, but recent reports suggest a potential primary role for SGAs, especially in the setting of cardiac arrest [45, 46]. The most common SGAs in current North American prehospital use are the i‐gel™, the laryngeal tube (LT) airway, and the Laryngeal Mask Airway (LMA™). When EMS personnel have inserted an SGA instead of endotracheal tube, they should provide advance notification to the receiving ED since the SGA may require exchange to an endotracheal tube or surgical airway, and the receiving ED may need additional time to prepare or to assemble an appropriate team [47].
i‐gel
The i‐gel (Intersurgical, Inc., Liverpool, NY) (Figure 3.7) is a single lumen tube with a soft gel cuff that sits in the posterior oropharynx and seals around the perilaryngeal structure. There is no balloon to inflate. To insert the i‐gel, first lubricate the cuff and then advance the device along the posterior pharynx until resistance is encountered. At this time, the lip line on the i‐gel should align with the lips. It is then secured using a proprietary strap. A study of over 9,000 out‐of‐hospital cardiac arrest patients showed similar outcomes between individuals treated with i‐gel compared to intubation, suggesting a role as primary airway device in this setting [48]. Sizes are available for patients from 2 to >90 kg.
Figure 3.7 i‐gel.
Laryngeal tube
The LT is a SGA that consists of a single lumen tube (Figure 3.8). A single insufflation port simultaneously inflates two balloon cuffs. The LT design is supposed to facilitate more consistent placement in the esophagus than its predecessor, the esophageal‐tracheal Combitube®. Insertion of the LT airway is very similar to that of the Combitube. The rescuer inserts the LT blindly into the patient’s mouth, positioning the smaller distal balloon in the esophagus and the larger proximal balloon in the oropharynx. After balloon cuff inflation, the rescuer may need to withdraw the tube slightly to seal the balloon against the oropharyngeal structures.
Disposable versions of the device exist for prehospital application. There is also a version with an esophageal port permitting concurrent placement of an orogastric tube. Complications, while infrequent, can include laryngospasm, vasovagal asystole, and glottic hematoma [49]. In addition to three different adult sizes, pediatric sizes of the LT are also available. Given the simplicity of its design, the LT can be rapidly placed by EMS clinicians with a range of skills in a variety of clinical settings. In a randomized controlled trial of 3,000 adult out‐of‐hospital cardiac arrests, a strategy of initial LT use was associated with improved adult out‐of‐hospital cardiac arrest outcomes compared with a strategy of initial ETI [46, 49].
Figure 3.8 LT airway.
Laryngeal Mask Airway (LMA)
The LMA is an SGA originally designed for use in the operating room (Figure 3.9) [50]. The distal tip of the airway contains a spade‐shaped balloon designed to seal around the vocal cord structures. The rescuer inserts the device blindly through the oropharynx, positioning the cuff around the laryngeal structures. Inflation of the cuff facilitates proper sealing of the device.
Limited studies describe LMA use by EMS personnel [51]. Prehospital use in the United States remains relatively limited, possibly due to concerns of the device’s inability to prevent aspiration and its potential for inadvertent dislodgement. A variation is the LMA Fastrach, or Intubating LMA, which is designed to facilitate insertion of an endotracheal tube. Disposable versions of both the LMA and the LMA Fastrach currently exist. Pediatric sizes are available.
Other supraglottic airways
The Combitube is a double‐lumen tube with a
